title: Preserved antibody levels and loss of memory B cells against pneumococcus and tetanus after splenectomy: tailoring better vaccination strategies.
abstract: Splenectomized patients are exposed to an increased risk of septicemia caused by encapsulated bacteria. Defense against infection is ensured by preformed serum antibodies produced by long-lived plasma cells and by memory B cells that secrete immunoglobulin in response to specific antigenic stimuli. Studying a group of asplenic individuals (57 adults and 21 children) without additional immunologic defects, we found that spleen removal does not alter serum anti-pneumococcal polysaccharide (PnPS) IgG concentration, but reduces the number of PnPS-specific memory B cells, of both IgM and IgG isotypes. The number of specific memory B cells was low in splenectomized adults and children that had received the PnPS vaccine either before or after splenectomy. Seven children were given the 13-valent pneumococcal conjugated vaccine after splenectomy. In this group, the number of PnPS-specific IgG memory B cells was similar to that of eusplenic children, suggesting that pneumococcal conjugated vaccine administered after splenectomy is able to restore the pool of anti-PnPS IgG memory B cells. Our data further elucidate the crucial role of the spleen in the immunological response to infections caused by encapsulated bacteria and suggest that glycoconjugated vaccines may be the most suitable choice to generate IgG-mediated protection in these patients.
authors.affiliation: Immunology Area, Bambino Gesù Children's Hospital IRCCS, Rome, Italy.
authors.forename: M Manuela
authors.initials: MM
authors.lastname: Rosado
authors.forename: Francesco
authors.initials: F
authors.lastname: Gesualdo
authors.forename: Valentina
authors.initials: V
authors.lastname: Marcellini
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Sabatino
authors.forename: Gino Roberto
authors.initials: GR
authors.lastname: Corazza
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Smacchia
authors.forename: Bruno
authors.initials: B
authors.lastname: Nobili
authors.forename: Carlo
authors.initials: C
authors.lastname: Baronci
authors.forename: Lidia
authors.initials: L
authors.lastname: Russo
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossi
authors.forename: Rita De
authors.initials: RD
authors.lastname: Vito
authors.forename: Luciana
authors.initials: L
authors.lastname: Nicolosi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Inserra
authors.forename: Franco
authors.initials: F
authors.lastname: Locatelli
authors.forename: Alberto E
authors.initials: AE
authors.lastname: Tozzi
authors.forename: Rita
authors.initials: R
authors.lastname: Carsetti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D007223:Infant; D008297:Male; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000276:immunology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000008:administration & dosage; D011135:Polysaccharides, Bacterial / Q000276:immunology; D013154:Spleen / Q000276:immunology*; D013156:Splenectomy; D013742:Tetanus / Q000276:immunology; D014611:Vaccination / Q000379:methods*; D055815:Young Adult
chemical_list: C538862:13-valent pneumococcal vaccine; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines; D011135:Polysaccharides, Bacterial
keywords: Asplenia; Memory B cells; Serum anti-PnPS; Splenectomy; Streptococcus pneumoniae